Helmet Design And Lives Saved

The past fifteen years have seen significant advances in motorcycle helmet design and materials. As a result, the newer helmets afford a much greater degree of protection against potentially fatal head injuries. Despite these technological improvements, NHTSA is still using the 29 percent helmet effectiveness calculated from observed fatality data from the 1980’s.

This report uses more recent data from the Fatality Analysis Reporting System (FARS) to update the estimated protective value of motorcycle helmets in the prevention of fatal head injuries and to estimate the total number of lives saved by helmets. An “effectiveness” of 29 percent means that use of a proper helmet can improve a rider’s chances of surviving a potentially fatal crash by almost one-third. The fact that motorcyclist fatalities represent about nine percent of all passenger vehicle occupant deaths, despite the relatively low numbers of motorcycles vis-à-vis other passenger vehicles traveling the nation’s highways, underscores the protective value of motorcycle helmets.

In terms of lives saved, the 29 percent effectiveness means that over the recent ten-year period from 1993 through 2002, motorcycle helmets have saved 5,430 lives. This estimate is conservative, given the known improvements in helmet technology over the same period. If effectiveness were recalculated based on more recent mortality data, one would expect to see a higher effectiveness and a concomitant increase in the number of lives saved.

While helmets have improved, the proportion of riders who actually use them has declined. In the United States in 2002, motorcycle crashes claimed the lives of 3,244 motorcyclists and injured another 65,000. Many of these riders were not wearing helmets. In fact, the 2002 National Occupant Protection Use Survey (NOPUS) data on helmet usage shows that only 58 percent of motorcyclists wear helmets when they ride, a sharp drop from the 71 percent usage rate in 2000. With the repeal or watering down of helmet laws in many states, both the percentage of non-users and the number of fatalities have grown.

Since 1974, motorcycle helmets are required to meet or exceed the Department of Transportation’s Federal Motor Vehicle Safety Standard (FMVSS) No. 218. In addition, many helmet manufacturers voluntarily submit their products for testing and certification under the standards developed and periodically updated by private testing laboratories. In particular, the requirements of FMVSS 218, together with changes in design and materials used in manufacturing helmets, are the driving force behind the improved effectiveness of helmets. One of the more significant innovations introduced in the early 1990s has been the use of materials such as Kevlar, expanded polypropylene, and carbon fiber in the manufacture of helmet shells and protective linings.

Of course, head injuries are not the only cause of crash fatalities. When we speak of “effectiveness” of helmets in reducing the risk of death in fatal motorcycle crashes, all types of injuries suffered by riders are included by implication. For example, if a helmet were absolutely certain to prevent a severe head injury, the rider could still die from other traumatic injuries suffered in a crash. Clearly, motorcycle helmets cannot prevent all fatal injuries, but in the case of head injuries in particular, helmets do provide a measure of preventive protection to the wearer. Just how effective helmets are in preventing fatalities is a function of both their performance in crashes and the incidence of fatal injuries other than head injuries. While it would be useful to know the effectiveness of helmets in preventing potentially fatal head injuries alone, the purpose of effectiveness as calculated here is to provide a measure of the overall difference in survival value in a potentially fatal crash that is attributable to the proper use of a helmet.

A number of studies have shown helmets to be an important factor in preventing death or serious injury in motorcycle crashes. Braddock, Schwartz et al. (1992), found that un-helmeted motorcyclists were 3.4 times more likely to die than were helmeted riders. A study by Kelly, Sanson et al. (1991) found that injured non-helmeted riders had higher injury severity scores and sustained more head and neck injuries. Of the 26 fatally injured riders in this study, 25 were un-helmeted. A three year study of helmet use in Colorado found that following repeal of a helmet law in 1977, helmet usage declined from 99 percent to as low as 49 percent, while the motorcycle fatal crash rate increased by more than 100 percent and the injury crash rate increased by 13 percent. More recently, a 2003 evaluation of the repeal of helmet laws in Kentucky and Louisiana found that in both states, the helmet use rate declined rapidly in the years following repeal, from 96 percent to 56 percent in Kentucky and from about 100 percent to 52 percent in Louisiana, while the fatalities increased correspondingly in both states.

In support of revisiting motorcycle helmet effectiveness in saving lives, an analysis of data from the Department of Transportation’s Crash Outcome Data Evaluation System (CODES) in 1996 showed that “…motorcycle helmets are 35 percent effective in preventing fatality, 26 percent effective in preventing injuries at least serious enough to require transport to the hospital ED [Emergency Department], and 9 percent effective in preventing all injury.”